The mind-brain dichotomy has been on a roller-coaster ride over the past few hundred years. Clinically astute European neuropsychiatrists in the 18th and 19th centuries described various neuropsychiatric disorders based on observations of their patients. The most fitting example of these are descriptions of patients with neurosyphilis, also known in the 18th and 19th centuries as general paresis of the insane. This era was followed by Freudian influences on psychoanalytical theories. It is an interesting observation that, historically, schizophrenia was initially described by Emil Kraepelin as dementia praecox, an organic terminology. Psychoanalysts later attributed development of schizophrenia to a schizophrenogenic mother. Advances in the neurosciences in the past few decades have exonerated mothers worldwide by establishing a neurodevelopmental hypothesis of schizophrenia.

The mind-brain dichotomy has created 2 different disciplines in medicine: neurology and psychiatry. The training of psychiatric residents has focused on identifying and treating behavioral and psychological symptoms based on a cookbook approach using DSM. Unfortunately, the inadequate training of psychiatric residents in neurology, especially in behavioral neurology, has future implications for clinical practice.

Avoiding diagnostic errors

Spitzer described 2 types of errors that lead to misdiagnosis as "functional" psychiatric disorders. These are informational errors (failure to gather clinical and historical data vital to make a correct diagnosis) and criterion errors (data are collected but the clinician fails to recognize the illness).1 Geschwind, arguably the progenitor of modern behavioral neurology, emphasized that an incomplete history taking and the failure to recognize regional brain syndromes leads to incorrect diagnoses.1 Tucker, another noted contemporary neuropsychiatrist, emphasized paying attention to the clinical course of the disease.1 Clinicians often rely heavily on fitting symptom clusters into diagnostic categories. There are also some systemic issues, such as insufficient time for evaluation, fragmented care, lack of communication between providers, and lack of adequate neurology training during residency training. Fortunately, for the purpose of diagnosis, there are certain clinical features that various organic psychiatric disorders tend to have in common.1 Bonhoeffer observed that different varieties of pathological conditions are often associated with similar forms of impairment.1 Psychiatric presentations of medical origin have certain features in common (Table 1).

Acute organic conditions usually have a fairly rapid onset and may present with cognitive deficits and fluctuating mental status, incoherent thought processes, lack of insight, perceptual disturbances, and delusions. Hallucinations are usually visual in organic conditions. In contrast, chronic organic conditions usually have an insidious onset. Family or coworkers may notice a general intellectual decline. Other common features are egocentricity, lack of concern for others, deterioration of personal hygiene, hoarding behavior, and slowed thinking.

Neurological disorders

There are certain clinical features specific to different cerebral regions. For example, frontal lobe disorders usually present with personality changes. These may include disinhibition or apathy (pseudomania and pseudodepression). Also common are lack of concern for others, lack of insight and judgment, and executive function deficits. Often the frontal lobe lesions are silent for a long time, ie, they can grow large before declaring themselves neurologically. Parietal lobe lesions usually cause complex cognitive deficits that are diffi- cult to detect on routine mental status examination or by using the Mini-Mental State Examination (MMSE). Visuo-spatial difficulties, constructional dyspraxias, and topographical disorientation are common as are personality changes with intellectual and neurological deficits (Table 2).

Seizure disorders

There is a plethora of literature on the neuropsychiatric aspects of epilepsy1,2; only a few salient points are discussed here. An undiagnosed seizure disorder may disclose itself with delirium, bizarre behavior, and psychotic symptoms. Without a high index of clinical suspicion and aggressive diagnostic workup, seizure disorders may remain undiagnosed for a long period. Frontal lobe seizures often manifest with a bizarre clinical picture.1 Automatisms, such as rubbing, kicking, and arm flailing, may be present. Sexual automatisms, such as pelvic thrusting and genital manipulation, may be seen. The patient may engage in vocalizations, shouting, screaming, and disinhibited behaviors, which may lead to a misdiagnosis of mania, psychosis, or pseudoseizures.